Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowances for accounts receivable	$ 10,114	$ 8,792
Accumulated amortization of intangibles	$ 55,667	$ 49,010
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	300,000,000	300,000,000
Common stock, shares issued	87,850,292	87,850,292
Treasury stock, shares	31,094,620	29,698,893